Web jsp开发学习——Servlet提交表单时用法

实现提交表单以后判断输入的信息是否符合条件

若符合条件

先新建servlet

再到web.xml里注册

register.jsp就是表单的界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"
    errorPage="error.jsp"%>
<%
    String ser_msg = (String)request.getAttribute("server_info");
%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<link href="css/style.css" rel="stylesheet" type="text/css"/>
<style>
dl{width: 500px;}
dt{width: 80px; float: left; height: 40px; text-align: right;}
dd{width: 360px; float: left; height: 40px; margin: 0px 0px 0px 10px;}
input[type=text],input[type=password]{width: 300px; height: 25px; border-radius: 10px; border solid 2px #999;}
#main{
    width:400px;
    margin:auto;
}
#main h2{
    text-aligh:center;
    margin-left:100px;
}
#info{color:#f00; font-weight:bold;}
</style>
<script>
</script>
<body>
<div id="main" >
<h2>用户注册</h2>
<!-- 提交，发生动作 reg_action.jsp-->
<form action="reg" method="post">
    <dl>
        <dt>用户名：</dt><dd><input type="text" name="usercode"></dd>
        <dt>密码：</dt><dd><input type="password" name="userpass"></dd>
        <dt>确认密码：</dt><dd><input type="password" name="confpass"></dd>
        <dt>姓名：</dt><dd><input type="text" name="username"></dd>
        <dt>Email：</dt><dd><input type="text" name="email"></dd>
        <dt>性别：</dt><dd><input type="radio" name="gender" value="0" checked>
            男 <input type="radio" name="gender" value="1">女</dd>
        <dt>职业：</dt><dd><select name="occupation">
            <option value="a">战士（Warrior）</option>
            <option value="b">坦克（Tank）</option>
            <option value="c">刺客（Assassin）</option>
            <option value="d">法师（Mage）</option>
            <option value="e">射手（Archer）</option>
            <option value="f">辅助（Support）</option>
        </select></dd>
        <dt>兴趣爱好：</dt><dd><input type="checkbox" name="hobby" value="吃饭">吃饭
    <input type="checkbox" name="hobby" value="睡觉">睡觉
    <input type="checkbox" name="hobby" value="豆豆">打豆豆</dd>
        <dt>出生日期：</dt><dd><input type="date" name="birthday"></dd>
        <dt>照片：</dt><dd><input type="file" name="photo"></dd>
        <dt>自我介绍：</dt><dd><textarea name="introduce"></textarea></dd>
        <dt></dt><dd><input type="checkbox" name="read" value="1">我已阅读《用户协议》</dd>
    
        <%=ser_msg == null? "":"<dt></dt><dd><span id='info'>"+ser_msg+"</span></dd>"%>
        <dt></dt><dd><input type="submit" value="注 册">&nbsp;&nbsp;
        <input type="reset" value="取 消"></dd>
    </dl>
</form>
</div>
</body>
</html>

在servlet里的doGet里写判断语句

前端register.jsp获取servlet传来的msg

doGet代码

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        String ucode = request.getParameter("usercode");
        String msg;
        RequestDispatcher rd = request.getRequestDispatcher("register.jsp");
        PrintWriter out = response.getWriter();
        out.print("usercode: " + ucode);
        if(ucode.equals("管理员")){
            //response.sendRedirect("register.jsp");页面跳转
            msg = ucode + "不能使用！";
            request.setAttribute("server_info", msg);
            
            rd.forward(request, response);
        }
        if(ucode.length()<8 || ucode.length()>20){
            msg = ucode+"长度不符合要求";
            request.setAttribute("server_info", msg);
            rd.forward(request, response);
        }
        if(!Tools.checkChar(ucode)) {
            msg = ucode+"包含非法字符";
            request.setAttribute("server_info", msg);
            rd.forward(request, response);
        }

    }

Tools.java是我用来专门处理不符合条件的一个java代码，全写进servlet里太乱了，之后要写入到Tools里

servlet前面导入一下

Tools.java的代码如下：

package com.xx17.cys.base;

public class Tools {
    
    public static int getNum(String str) {
        int result = 0;
        try{
            if(str.length()>0) {
                result = Integer.parseInt(str);
            }
        }catch(Exception e){
        }
        return result;
    }
    
    /*
     * 判断是否包含非法字符
     * 返回：包含（false）、不包含（true）
     * 修改：cys,2019-4-4
     * */
    public static boolean checkChar(String str) {
        boolean result = true;
        String validStr="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
        for(int i=0; i<str.length();i++) {
            String s = str.substring(i, i+1);
            if(validStr.indexOf(s)==-1) {
                System.out.println(s+"非法字符！！！");
                result = false;
                break;
            }
        }
        return result;
    }
}

Web jsp开发学习——Servlet提交表单时用法

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